Cisco Cisco IOS Software Release 12.2(11)T

This document describes the Session Initiation Protocol for Voice over IP feature for Cisco uBR925 
cable access routers and Cisco CVA122 Cable Voice Adapters in Cisco IOS Release 12.2(11)T. This 
document provides information on configuring the Session Initiation Protocol for Voice over IP feature 
to enable the setup of voice and multimedia calls across Internet Protocol (IP) networks.

This document includes the following sections:

The Cisco Session Initiation Protocol (SIP) functionality enables Cisco access platforms to signal the 
setup of voice and multimedia calls over IP networks. 

SIP is an ASCII-based, application-layer control protocol that can be used to establish, maintain, and 
terminate calls between two or more endpoints. SIP is an alternative protocol developed by the Internet 
Engineering Task Force (IETF) for multimedia conferencing over IP. SIP features are compliant with 
IETF RFC 2543, SIP: Session Initiation Protocol, published in March 1999. You can view RFC 2543 at 

http://www.ietf.org/rfc/rfc2543.txt

. 

12.2(11)T

Support for the Session Initiation Protocol for Voice over IP feature was 
introduced for Cisco uBR925 cable access routers and Cisco CVA122 
Cable Voice Adapters.